Refactor `modules/desktop/options.nix` to improve code readability by
expanding the `optPath` list definition and simplifying the
`wisdomSimpleSlice` configuration logic.
Also apply minor style fixes to `modules/wisdom/filebrowsers/nemo.nix`
to ensure consistent spacing within list definitions.
Move Home Manager module defaults from a centralized `desktop-home-defaults.nix`
file into their respective `wisdom` slices. This change aligns with the
updated documentation regarding module ownership, where defaults live
with the option that owns them rather than in a shared defaults file.
Additionally, update `docs/conventions.md` to reflect this new pattern for
defining `mkEnableOption` defaults and move base git/encryption
configurations into the core `wisdom` module.
- Delete `modules/hosts/desktop-home-defaults.nix`
- Update `modules/wisdom/default.nix` to include shared git and package defaults
- Add `default = ...` to `mkEnableOption` in various `wisdom` modules
- Update `docs/conventions.md` with new HM slice guidelines
Olivier